There is a critical need to improve the accuracy of preclinical drug efficacy screening and testing through the development of in vitro culture systems that more effectively mimic the in vivo environment. Systems to properly recreate the tumor microenvironment are essential to advance the discovery and development of effective anticancer agents. HemoShear, LLC is a biotechnology research company that utilizes patented methodologies (US 7,811,782) to restore in vivo biology to human primary cells in co-culture on the bench. We have commercialized two multicellular human organ systems that mimic the microenvironment of the vasculature and the liver for drug discovery and development. In the HemoShear systems, the cell types now respond to drugs and hormones at concentrations that are nearer to human in vivo levels. In the HemoSehar technology, heterotypic cell-cell communication, hemodynamic flow and transport are all necessary for restoring in vivo response on the bench. These principles also apply to tumor biology in vivo. Microvascular cells in a tumor are affected by blood flow and communicate with tumor and non-tumor cells physically and through diffusible factors. In this contract, we will utilize the HemoShear technology to develop a human tumor microenvironment system.